Primary structures of hypertrehalosaemic neuropeptides isolated from the corpora cardiaca of the cockroaches Leucophaea maderae, Gromphadorhina portentosa, Blattella germanica and Blatta orientalis and of the stick insect Extatosoma tiaratum assigned by tandem fast atom bombardment mass spectrometry

Hypertrehalosaemic peptides were isolated by reversed-phase high-performance liquid chromatography from corpora cardiaca of four species of cockroaches (Leucophaea maderae, Gromphadorhina portentosa, Blattella germanica, and Blatta orientalis) and one stick insect species (Extatosoma tiaratum), and their primary sequences were assigned by collision-induced decomposition tandem fast atom bombardment mass spectrometry (FABMS/CID/MS). The members of the cockroach families Blaberidae (L. maderae and G. portentosa) and Blattellidae (B. germanica) contained an identical decapeptide (Glu-Val-Asn-Phe-Ser-Pro-Gly-Trp-Gly-ThrNH2), whereas the member of the cockroach family Blattidae (B. orientalis) had two octapeptides (Glu-Val-Asn-Phe-Ser-Pro-Asn-TrpNH2 and Glu-Leu-Thr-Phe-Thr-Pro-Asn-TrpNH2). The structure of the stick insect hypertrehalosaemic compound was assigned as a decapeptide (Glu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-Gly-ThrNH2). The respective synthetic peptides elevated blood carbohydrates in their respective acceptor species. The results are discussed in the light of family-specificity of members of the adipokinetic hormone/red pigment-concentrating hormone family.     

Differential consumption of baits by pest blattid and blattellid cockroaches and resulting direct and secondary effects

Consumption was measured of three commercially available cockroach gel baits (0.01 and 0.05% fipronil and 0.6% indoxacarb) by two pest blattellid (German cockroach, Blattella germanica L., and brownbanded cockroach, Supella longipalpa Fabricius) and three pest blattid [oriental cockroach, Blatta orientalis L., American cockroach, Periplaneta americana L., and smokybrown cockroach, Periplaneta fuliginosa (Serville)] species (Dictyoptera), and direct and secondary effects were quantified. All three baits were greatly preferred for consumption over dog food; however, virtually all consumption (ca. 98%) by pest blattids was gel baits containing sugar feeding stimulants and water. Pest blattid greater preference for gel baits was probably due to their greater need for nutrients in baits due to their greater cuticular water permeability and higher metabolism than the pest blattellids. Brownbanded cockroaches had lowest percentage gel bait selection. Pest blattellids consumed greater amounts of bait per g body weight than pest blattids. Cockroaches consumed more active ingredient than needed to cause mortality; however, based on bait consumption, a 30‐g tube of gel bait potentially killed from 394 to 6 966 adult cockroaches, depending on species. Mortality for all cockroach species was faster for adults (≥3 days) than for nymphs (≥7 days); however, most brownbanded cockroaches exposed to indoxacarb survived despite consuming 1.5‐ to >3‐fold more than other baits, suggesting low enzyme production by brownbanded cockroaches and consequently lower conversion of indoxacarb into its toxic form. Besides direct mortality, German cockroaches died from indirect effects: exposure to debris from other cockroaches that had direct access to the gel baits or bait contact without ingestion. Although maximization of bait consumption is important, factors that enhance secondary mortality and contact toxicity should also be considered.     

Toxicity of abamectin to cockroaches (Dictyoptera: Blattellidae, Blattidae).

Abamectin was fed to German cockroaches, Blattella germanica (L.), in non-choice tests. LT50s and LC50s were estimated by probit analysis. The LT50s for the German cockroach ranged from 4.4 to 1.7 d for males, from 9.0 to 2.4 d for females, and from 4.4 to 1.6 d for nymphs for bait concentrations of abamectin between 0.0025 and 0.0500%. The LC50s of abamectin were 0.0110 and 0.0040% from males, 0.0240 and 0.0090% for females, and 0.0200 and 0.0080% for nymphs at 3 and 6 d, respectively. The LT50 values of 0.0550% abamectin bait were 3.4, 3.4, 2.4, 7.5, 2.9, and 4.5 d for Periplaneta americana (L.), P. fuliginosa (Serville), P. brunnea Burmeister, P. australasiae (F.), Blatta orientalis L., and Supella longipalpa (Serville). Although the bait was effective against various cockroach species, time to death for the larger species was longer than for the German cockroach. In preference tests in which male German cockroaches were allowed to feed on rat chow or abamectin bait, all died within 5 d of exposure to abamectin bait. Abamectin bait consumption was not significantly lower than that of untreated rat chow. Arena tests with 0.0550% abamectin bait resulted in 31-75% mortality of German cockroaches after 9 d, with most control being achieved by treating harborages with the bait. The hydramethylnon standard resulted in 65% mortality after 9 d.     

Effects of hydroprene on development and reproduction in the Oriental cockroach, Blatta orientalis

Nymphs of the Oriental cockroach Blatta orientalis were exposed during the penultimate and final instars to vinyl tiles treated with the juvenile hormone analogue hydroprene. Adults moulting from these nymphs exhibited deformities such as twisted wings in both sexes and modified genitalia in females. Females with deformities were unable to produce viable oothecae. B.orientalis confined on tiles treated with hydroprene at rates of 25-100 mg/m2 did not reproduce. The treatment rate of 10 mg/m2 reduced fecundity and caused 47-57% of resultant adults to have deformities, but some adults reproduced successfully and population growth was not suppressed.     

Juvenile hormone and methyl farnesoate production in cockroach embryos in relation to dorsal closure and the reproductive modes of different species of cockroaches

Juvenile hormone (JH), produced by the corpora allata (CA), is first detectable after dorsal closure, a conspicuous event in embryogenesis. The present research found that the timing of dorsal closure was consistently at about 45% of the total embryonic development time across most of the oviparous and ovoviviparous cockroach species examined. These included the ovoviviparous cockroaches Blaberus discoidalis, Byrsotria fumigata, Rhyparobia maderae, Nauphoeta cinerea, Phoetalia pallida, Schultesia lampyridiformis, and Panchlora nivea, as well as the oviparous cockroaches Blatta orientalis, Periplaneta americana, Eurycotis floridana, and Supella longipalpa. However, the only known viviparous cockroach Diploptera punctata completed dorsal closure at 20.8% of embryo development time. Methyl farnesoate (MF), the immediate precursor of JH III, is considered a functional molecule in crustaceans; however, in insects its function is still unclear. To understand the role of JH and MF in cockroach embryos, I compared JH and MF biosynthesis and release in several cockroach species of known phylogenetic relationships. Using a radiochemical assay, the present research showed that cockroach embryos representing all three reproductive modes produced and released both JH and MF, as previously shown for B. germanica, N. cinerea, and D. punctata. Members of a pair of embryonic CA from B. discoidalis, B. fumigata, R. maderae, and D. punctata were incubated with and without farnesol. MF accumulated in large amounts only in CA of R. maderae in the presence of farnesol, which indicates that control of the last step of biosynthesis of JH, conversion of MF into JH by MF epoxidase, is probably a rate-limiting step in this species.     

Nymphs of the Oriental cockroach (Blatta orientalis) as passive vectors of causal agents of avian tuberculosis and paratuberculosis

The potential transmission of the causal agent of paratuberculosis Mycobacterium avium ssp. paratuberculosis and avian tuberculosis Mycobacterium avium ssp. avium (Actinomycetales: Mycobacteriaceae) by nymphs of the Oriental cockroach Blatta orientalis L. (Blattodea: Blattidae) was investigated by oral infection with mycobacterial suspensions and examination of their droppings and bodies. Both the subspecies of M. avium were isolated from droppings at 3 days post-infection and M. a. avium was found in homogenized bodies at 10 days post-infection. The identity of M. a. avium and M. a. paratuberculosis isolates was demonstrated by Restriction Fragment Length Polymorphism (RFLP) analysis. The M. a. avium isolate used as the inoculum and the isolates from the bodies and droppings of the nymphs were shown to be virulent in chickens. The results show that orally infected nymphs of B. orientalis can harbour and shed viable and virulent mycobacteria. This hazard should be considered in the implementation of control measures against mycobacterial infections of animals and humans, which should include destruction of all developmental stages of cockroaches and prevention of their access to materials that can be contaminated by mycobacteria.     

The molecular evolution of the allatostatin precursor in cockroaches

Allatostatins (ASTs) of the Tyr/Phe-Xaa-Phe-Gly Leu/Ile-NH2 family are a group of insect neuropeptides that inhibit juvenile hormone biosynthesis by the corpora allata. We have obtained genomic DNA sequences that specify the preproallatostatin precursor for the cockroaches, Blatta orientalis, Blattella germanica, Blaberus (cranufer and Supella longipalpa. The sequences obtained are similar to those of Diploptera punctata and Periplaneta americana reported previously. The precursors of all these cockroach species are similar in size, and the organization of the ASTs that they contain (there are 13 or 14, depending on the species) have been conserved. With the sequences of these precursors, and using the homologous sequence in the orthopteran Schistocera gregari as an outgroup, a phylogenetic analysis using parsimony was carried out. The dendrograms obtained from these analyses. using the amino acid as well as the nucleotide sequences, are comparable with current models for cockroach phylogeny. Parsimony analysis was also used to study the genealogy of the different ASTs within the same precursor. Results suggest that the AST sequences were generated through a process of internal gene duplication which occurred before these species diverged from each other in evolutionary time.     

Morphogenetic effects of hydroprene on genitalia of the oriental cockroach (Dictyoptera: Blattidae)

Hydroprene had a considerable effect on the morphogenesis of external genitalia of the oriental cockroach, Blatta orientalis L. Exposure of nymphs to hydroprene resulted in abnormal adultoids with structural and positional distortions, and reduced or absent cuticular sclerotizations of the external genitalia. Late nymphal instars were significantly more sensitive to hydroprene than were early instars. In males, the epithelial cells of wings, serrata of the right phallomere, titillator and other lobes of the left phallomere were sensitive to hydroprene. The left phallomere was often prolapsed, distorted, and reduced in sclerotization. The right phallomere, particularly the serrata, was extremely malformed. In severe cases, phallomeres were entirely distorted or fused to each other. In females, the overall structure of the ovipositor appeared flaccid, less sclerotized, and misshapen. The first and second pairs of valvulae were often misshapen and reduced in sclerotization and length, or even fused with the third valvulae. This study provides morphological evidence that B. orientalis with malformed genitalia after treatment with hydroprene would be unsuccessful in copulation and fertilization. A high correlation between wrinkled wings and malformed male genitalia can be an important criterion to evaluate the effects of hydroprene on this species.     

'Candidatus Rhabdochlamydia crassificans', an intracellular bacterial pathogen of the cockroach Blatta orientalis (Insecta: Blattodea)

The genus Rickettsiella comprises various intracellular bacterial pathogens of arthropods, exhibiting a chlamydia-like developmental cycle. Species may be divided into two main groups, the R. popilliae-R. grylli group and the R. chironomi group. Previous phylogenetic studies based on the 16S ribosomal RNA encoding gene showed that two Rickettsiella species, one from each group, belong in reality to two distantly related lineages, the gamma-Proteobacteria (R. grylli) and the Chlamydiales ('Candidatus Rhabdochlamydia porcellionis', a pathogen of terrestrial isopods). In the present work, the 16S rDNA sequence of another Rickettsiella-like species, causing abdominal swelling to its cockroach host Blatta orientalis, was determined and phylogenetic analysis performed. Identical 16S rDNA sequences of 1495 nucleotides were obtained from fat body and ovary tissues of both healthy and diseased cockroach individuals. The sequence shared only 73% of similarity with R. grylli, but 82-87% with most Chlamydiales, and even 96.3% with 'Candidatus Rhabdochlamydia porcellionis'. Phylogenetic analyses confirmed the affiliation of the cockroach pathogen within the order Chlamydiales, and based on ultrastructural characteristics and genetic analyses, we propose its inclusion in the 'Candidatus Rhabdochlamydia' as a distinct taxon, 'Candidatus Rhabdochlamydia crassificans'. These results extend our knowledge of the phylogenetic diversity of the Chlamydiales.     

Broad infectivity of Leidynema appendiculatum (Nematoda: Oxyurida: Thelastomatidae) parasite of the smokybrown cockroach Periplaneta fuliginosa (Blattodea: Blattidae)

Host specificity of parasites is important for the understanding of evolutionary strategies of parasitism that would be a basis of predictions of the disease expansion when parasitized hosts invade new environments. The nematode order Oxyurida is an interesting parasite group for studying the evolution of parasitism as it includes parasites of both invertebrates and vertebrates. In our survey, we found that the smokybrown cockroach Periplaneta fuliginosa was primarily infected with only one nematode species Leidynema appendiculatum. In two cases, L. appendiculatum was isolated from two additional cockroach species Pycnoscelus surinamensis, sold in Japan as a reptile food, and Blatta lateralis, captured in the field and cultured in the laboratory. Inoculation of L. appendiculatum into three additional cockroach species P. japonica, Blattella nipponica, and P. surinamensis also resulted in parasitism. Infection prevalence was high, and timing of postembryonic development from hatched nematode larva to mature adult in these hosts was identical with that in P. fuliginosa. While ecological interactions strongly determine the host range, such broad infectivity is still possible in this parasitic nematode.     

Light and electron microscopic study of a Rickettsiella species from the cockroach Blatta orientalis

An infection with Rickettsiella sp. was responsible for an illness causing heavy body swelling in the Oriental cockroach Blatta orientalis. Reproduction of the colony stagnated. Vacuoles with parasitic bacteria occurred mainly in the fat body, but also in nearly all other organs, such as gut epithelium, Malpighian tubules, blood cells, and ovarioles. The parasites clearly differed from the symbiotic bacteria of the genus Blattabacterium, which regularly occur in the mycetocytes of B. orientalis. The vacuoles contained four stages of Rickettsiella: (1) infectious, electron-dense, rod-like elementary bodies (mean size 300 x 145 nm); (2) an electron-dense, flat intermedium stage, called flat body (mean size 515 x 255 x 125 nm); (3) an electron-light, spherical intermedium stage, called condensing sphere (mean size 340 nm); portions of cytoplasm condensed crescent-like at the border or in the center of the cell; and (4) large, spherical, electron-light initial bodies that multiplied by binary fission (mean size 600 nm). The initial bodies had a three-layered cell boundary, but all other stages had a five-layered cell boundary. Elementary and flat bodies contained an electron-light, oblique lamella and an oval structure with an array of ribosome-like granules, respectively. In contrast to other species of Rickettsiella, crystal formation or multiple division did not occur. The described species of Rickettsiella is different from "R. blattae," which belongs to the R. popilliae group. Instead, it shares more similarities with the R. chironomi group. To avoid confusion, it was provisionally named "R. crassificans."     

Pathogenicity of intrathoracically administrated Bacillus thuringiensis spores in Blatta orientalis

The ability of Bacillus thuringiensis to produce septicaemia in Periplaneta americana and Blatta orientalis has been investigated. Spores and crystals from several wild-type strains as well as spores of a B. thuringiensis crystal-deficient mutant, were first orally administrated at high doses, and no significant mortality was recorded. Intrathoracic injection of spore suspensions in P. americana revealed that this species is not very susceptible to B. thuringiensis spores. B. orientalis, by contrast, was found to be very susceptible to B. thuringiensis, with a LD(50) of about 35,000 spores, that is similar to that reported on Lepidoptera challenged with parenterally injected B. thuringiensis.     

Reproductive and developmental biology of the oriental cockroach Blatta orientalis (Dictyoptera)

At 27 degrees C and 45% r.h. in the laboratory, the oriental cockroach Blatta orientalis (L.) developed to adulthood in seven to nine instars for males (66% had eight instars) and eight to ten instars for females (67% had nine instars) in mixed groups, with up to twelve instars for isolated females. Nymphal development lasted 185 +/- 2 days for males, 216 +/- 4 days for females, with 89% survival to adulthood. Adult longevity was significantly more for males than females in mixed groups. Virgin females lived for 135 +/- 6 days compared with 87 +/- 9 days for females kept with males. After an initial maturation time of 12.2-13.5 +/- 0.4 days for mated and unmated females, oothecae were produced, on average, every 6-7 (range 2-29) days. Ootheca viability was 68% from females kept with males, 32% from females kept apart from males. Numbers of nymphs emerging were 14.1 +/- 0.26 after 45 days from mated female oothecae 8.2 +/- 0.3 after 49 days from unmated females. With sexual reproduction the sex ratio of progeny reaching adulthood was 1.1 males per female (n = 443), whereas unmated females produced only female progency, which is consistent with parthenogenetic reproduction. Drawings of the ventral aspect of the terminalia are given to show features useful for instar determination and for distinguishing between male and female nymphs and adults of B. orientalis.     

Effect of the corpora allata on the development of the male accessory sex glands in Blatta orientalis]

The volumetric changes of the corpora allata (CA) during the first 15 days of imaginal life of Blatta orientalis L. (Dictyoptera, Blattidae) are studied in connection with the growth of the accessory reproductive glands (GSAM). Both, the CA and the GSAM, grow in parallel during the first 3-4 days of imaginal life, which suggests a possible functional link between both organs. If the CA are explained on freshly ecdysed adults, then GSAM protein accumulation is reduced (by 35%) when checked on day 5, and administration of juvenile hormone (JH) restores normal development. However, when the effects of allatectomy are studied on day 12, no significant differences with respect to the controls are observed. These results suggest that JH is not strictly necessary for protein synthesis in the GSAM of B. orientalis although it has a stimulatory effect on this synthesis.     

Avian haematozoa: some taxonomic and nomenclatural problems arising from the Russian literature.

It is evident from a survey of the Russian literature that many species of avian haematozoa recorded do not meet the basic criteria required by the International Code of Zoological Nomenclature. Thus 28 species of Haemoproteus and 4 species of Leucocytozoon are considered to be nomina nuda, while 1 species, Leucocytozoon turtur orientalis is a synonym of L. marchouxi.     

Axonal transport involvement in long-lasting synaptic modifications in Blatta orientalis

To determine whether axonal transport plays a role in the establishment of long-lasting changes in synaptic transmission, the effects of colchicine on transport and on synaptic modifications induced by hyperactivity were studied in the nerve cord of the cockroach Blatta orientalis. Application of a lead weight on the insect's dorsum, and the consequent exaggerated use of antigravity reflexes, facilitated synaptic transmission along a particular nervous pathway in the metathoracic ganglion. Application of colchicine in the prothoracic ganglion reversibly blocked such synaptic facilitation and temporarily interfered with the transport of proteins along the cord. Five components of axonal transport, moving at 2, 10, 25, 75, and 150 mm/day, were altered by colchicine treatment with a temporal course that coincided with the reversible inhibition of synaptic facilitation. These results were brought about by colchicine acting directly on axonal transport at the level of the prothoracic ganglion, rather than on synaptic transmission measured at the metathoracic ganglion. The temporal correlation observed between the effects of colchicine on axonal transport and on synaptic facilitation strongly suggest that the transport process is essential for long-lasting synaptic modifications to take place.     

Ultrastructural and cytochemical observation of calcium ion localization in the black-beetle pleural muscles

The authors examined the infrastructure and distribution of calcium ions in the plexural muscles of a black-beetle (Blatta orientalis L.) after being fixed in a solution of osmiumtetroxide buffered with a cacodylate buffer (pH = 7.4) and according to the method of Carasso-Favard (1966). The infrastructure of these muscles differs from the muscles of other insects, first of all, in the amount and distribution of the sarcoplasmic net (SR) and mitochondria and also in the amount and topography of the location of lead precipitations which mark the calcium ions. The authors ascertained an intensive and permanent positive reaction to the presence of calcium in the mitochondria and sarcotubular systems of the sarcoplasmic reticulum, and in the intrafibrillar spaces and in the Z and M lines of the sarcomeres calcium concentrations are not detectable. The authors checked the results by using the method of Carasso-Favard (1966).     

Effect of carbon dioxide on the Oriental cockroach Blatta orientalis

Exposure to high concentrations of carbon dioxide (CO2) killed adult and nymphal stages of the oriental cockroach Blatta orientalis L. (Dictyoptera: Blattidae) with LT50 values of 11.5-16.2 h for 60% CO2 in air and 5.7-7.1 h for 100% CO2 at 20 degrees C; corresponding LT50s at 28 degrees C were 2.8-4.6 h for 60% CO2 in air and 2.3-3.6 h for 100% CO2. Complete kill of mobile stages was obtained within 24 h using 60% CO2 at 20 degrees C. Survivors of treatments with 100% CO2 at 28 degrees C remained completely paralysed for up to 3 days post-treatment and took up to 5 days to regain normal movement, but adult females then resumed production of oothecae with no significant loss in fecundity. Oothecae 5 or 30 days after deposition required 60-84 h exposure to 60% CO2 at 20 degrees C to prevent emergence of nymphs but less time using 100% CO2 at 28 degrees C. At 28 degrees C, when adult females were treated with 100% CO2 and 52% r.h. for 6 h (giving 100% mortality) loss of weight was significantly greater than that following treatment with air at 52% r.h. for 6 h (giving no mortality). However, significantly greater weight loss also occurred when they were treated with dried air (< 10% r.h.) for 6 h, also with no mortality. The toxicity of CO2 to mobile stages of the oriental cockroach appeared to result from irreversible effects on the nervous system, rather than from water loss during exposure.     

Sense organs on the antennal flagellum of a giant cockroach, Gromphadorhina portentosa, and a comparison with those of several other species (Dictyoptera, Blattaria)

Two kinds of tactile hairs, plain and wavy, thick-walled chemoreceptors and two types of thin-walled chemoreceptors are present on the antennal flagellum of Gromphadorhina portentosa males. These are described and their location on the antenna noted. Females of this species have plain tactile hairs and the same types of chemoreceptors as do the males but wavy tactile hairs are absent. The antennal sense organs of a few specimens of five other species of cockroaches — Periplaneta americana, Blatta orientalis, Supella longipalpa, Pycnoscelus surinamensis and Diploptera punctata — were also examined. All lacked tactile hairs but were provided with thick-walled chemoreceptors and with two types of thin-walled chemoreceptors similar to those described for Gromphadorhina portentosa.